Engines, such as those which power aircraft and industrial equipment, employ a compressor to compress air that is drawn into the engine and a turbine to capture energy associated with a combustion of a fuel-air mixture. Bearing support assemblies are used to support engine hardware. For example, and referring to FIG. 2, a bearing support assembly 200 in accordance with the prior art is shown. The bearing support assembly 200 includes a bearing centering spring/squirrel cage (illustrated via a centering spring beam 212), a stationary housing 214, and a bearing assembly 216. The centering spring beam 212 is defined by/between a first end 218 and a second end 220. The first end 218 includes a mounting flange 224 that is held in mated assembly with the housing 214. The bearing assembly 216 includes a bearing element 234, a first (e.g., inner) ring 236, and a second (e.g., outer) ring 238. A bearing assembly may be a roller bearing, ball bearing or some other type of bearing. The second end 220 of the centering spring beam 212 is coupled to the outer ring 238. The bearing support assembly 200 is shown defined about a longitudinal centerline 250. The centerline 250 may coincide with an engine axial centerline.
While a single centering spring beam 212 is shown in FIG. 2, conventionally a number of centering spring beams are replicated/distributed around the circumference of the centering spring. For example, approximately thirty centering spring beams may be used in some engines. The bearing support assembly 200 (in particular, the centering spring) is used to isolate vibration. For example, vibration that may be caused by rotation of engine hardware may be isolated by the centering spring; the centering spring may bend/deflect in response to loads experienced by the bearing assembly 216. Additionally, the centering spring may be used to accommodate rotor-dynamics; e.g., a stiffness of the centering spring may be customized/tailored to satisfy engine design requirements/criteria. A beam of the centering spring (see, e.g., FIG. 3B: beams 212a-212e) is oriented in a single direction (e.g., conventionally, parallel to an engine longitudinal axis/centerline).
For a given engine load/deflection, the amount of stress imposed on the centering spring beam 212 is related to a length of the centering spring beam 212 . For example, all other conditions/parameters being equal, a second centering spring beam that is longer than a first baseline/reference centering spring beam will have less stress imposed on it than the first centering spring beam. Thus, from a stress perspective (which may be related to a lifetime of the centering spring beam—e.g., a reduction in stress imposed on the centering spring beam increases an operational lifetime of the centering spring beam), it is desirable to have as long a centering spring beam as possible. However, all other conditions/parameters being equal, longer centering spring beams are heavier (which may reduce engine efficiency) and consume more space (where space may be limited); thus, in some respects, it is desirable to have as short a centering spring beam as possible. Thus, using conventional centering spring beams a trade-off must be made in terms of stress/lifetime on the one hand and weight/efficiency and space on the other hand.